EP3293552B1

EP3293552B1 - System and method for editing geological models by switching between volume-based models and surface-based structural models augmented with stratigraphic fiber bundles

Info

Publication number: EP3293552B1
Application number: EP17189692.1A
Authority: EP
Inventors: Romain MERLAND; Anne-Laure Tertois; Wan-Chiu Li
Original assignee: Emerson Paradigm Holding LLC
Current assignee: Emerson Paradigm Holding LLC
Priority date: 2016-09-07
Filing date: 2017-09-06
Publication date: 2021-05-26
Anticipated expiration: 2037-09-06
Also published as: US20180067229A1; EP3293552A1; US10466388B2

Description

FIELD OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention pertain to the general field of geological modeling of stratified terrains in a subsurface region of the Earth. More specifically, embodiments of the present invention relate to editing geological models.

BACKGROUND OF THE INVENTION

Geological models arc used to image regions of the Earth's subsurface, for example, in applications related to the oil and gas industry. In geological modeling, a geological region may be represented by a "surface-based" model or a "volume-based" model. A surface-based model may include a plurality of independently controllable surfaces of horizons and/or faults (e.g., with no interconnecting mesh between surfaces). A volume-based model may include surfaces with a 3D volumetric grid or mesh interconnecting the different geological surfaces.
Volume-based models are generally more efficient than surface-based models for executing flow and/or geomechanical simulations (e.g., used to determine petrophysical properties, such as porosity and permeability of the layers of the models) because volume-based models implicitly generate a plurality of horizons simultaneously and automatically ensure the horizons do not overlap, whereas surface-based models generate horizons one-at-a-time and cannot automatically prevent overlapping layers. However, surface-based models are generally more efficient than volume-based models for locally editing the models, for example, when simulation results differ from actual geological measurements. In surface-based models, control nodes are independently controllable so local edits remain generally contained within a single surface or defined region of a surface. In contrast, nodes of volume-based models are interconnected via a volumetric mesh, so local edits generally permeate throughout the entire model and require a global remodeling to unify the local edit to the remaining regions of the mesh.
Accordingly, there is a longstanding need in the art to gain the benefits of both surface-based and volume-based models.
US 8,473,115 B1 discloses a system in which a three-dimensional (3D) transformation may be generated between a 3D present day model having points representing present locations of the physical geological structures and a 3D past depositional model having points representing locations where the physical geological structures were originally deposited. An indication may be accepted to locally change the 3D transformation for a subset of sampling points in a first model of the models. The 3D transformation may be locally changed to fit the updated subset of sampling points. A locally altered or updated version of the first model and, e.g., second model, may be displayed where local changes to the first model are defined by the locally changed 3D transformation. The transformation may also be used to extract geobodies in the past depositional model.
EP2778725 (A2 ) discloses a method for computing and visualizing sedimentary attributes may include receiving paleo-geographic coordinates representing predicted approximate positions of particles of sediment deposited at a time period when a layer was originally formed. A sedimentation rate may be computed that varies laterally along the layer. A sedimentary attribute may be determined based on the lateral variation of the sedimentation rate along the layer with respect to the paleo-geographic coordinates.

SUMMARY OF EMBODIMENTS OF THE INVENTION

There is provided, a method implemented in a computing system of editing a volume-based model imaging geological structures according to claim 1, a system for editing a volume-based model imaging geological structures according to claim 10 and a computer-readable medium according to claim 11.
A plurality of surface meshes may be linked by a plurality of stratigraphic fibers to generate the surface-based model. The plurality of stratigraphic fibers may be updated, for example, by updating the geological time, based on the edited positions of the plurality of control nodes so as to fit the updated geological data. The edited surface-based model may be meshed to generate an updated volume-based model comprising a volumetric mesh defined by the edited positions of the control nodes. The updated volume-based model may be displayed.
In accordance with some embodiments of the present invention, the initial volume-based model may be received by first receiving an initial surface-based model, and meshing the initial surface-based model to convert into the initial volume-based model.
In accordance with some embodiments of the present invention, an initial paleo-depositional transform of the meshed initial surface-based model may be computed to generate a geological time of approximate time periods when particles of sediment were originally deposited to define the stratigraphy of surfaces in the initial volume-based model.
In accordance with some embodiments of the present invention, the plurality of stratigraphic fibers may include Iso-Paleo-Geological (IPG) lines having constant paleo-depositional coordinates and varying in geological time.
In accordance with some embodiments of the present invention, an invalid stratigraphic fiber from the plurality of stratigraphic fibers may be identified when the edited position of a control node along the stratigraphic fiber crosses to a different edited surface than initially positioned.
In accordance with some embodiments of the present invention, the identified invalid stratigraphic fibers may be repaired by constructing an intermediate volume-based model over one or more error zones that include the identified invalid stratigraphic fibers, computing a paleo-depositional transform of the intermediate volume-based model to extract a plurality of horizon surfaces and a plurality of stratigraphic fibers to generate a surface-based representation to fix the error zones.
In accordance with some embodiments of the present invention, the plurality of stratigraphic fibers may be updated by using an arc-length parametrization between the edited positions of the plurality of control nodes when the updated plurality of stratigraphic fibers includes uniform layering between pairs of horizon surfaces.
In accordance with some embodiments of the present invention, the plurality of stratigraphic fibers may be updated by adding secondary control nodes along the plurality of stratigraphic fibers at positions intersecting one or more intra-formational horizon surfaces in the updated geological data and interpolating along segments of the plurality of stratigraphic fibers adjacent to the added secondary nodes.
There is further provided, in accordance with some embodiments of the present invention, a device, system and method for editing a volume-based model imaging geological structures. An initial volume-based model may be received having initial geological data defined by a volumetric mesh including 3D cells. Updated geological data may be received defined within a region of the model. The volume-based model may be converted into a surface-based model of the initial geological data defined by a plurality of distinct surface meshes including 2D cells that form a plurality of horizon and fault surfaces linked by a plurality of 1D stratigraphic fibers defining the stratigraphic spacing between surfaces. The defined region of the surface-based model may be edited by editing the positions of a plurality of control nodes at the intersections of the 2D cells and the 1D stratigraphic fibers to conform to the updated geological data in the defined region of the model. The edited surface-based model of edited 2D cells and edited 1D stratigraphic fibers may be converted into an updated volume-based model of edited 3D cells. The updated volume-based model is stored.
In accordance with some embodiments of the present invention, the initial volume-based model may be received by receiving an initial surface-based model and meshing the initial surface-based model to convert into the initial volume-based model.
In accordance with some embodiments of the present invention, an invalid 1D stratigraphic fiber from the plurality of 1D stratigraphic fibers may be identified when the edited position of a control node along the 1D stratigraphic fiber crosses to a different edited surface than initially positioned.
In accordance with some embodiments of the present invention, the identified invalid 1D stratigraphic fibers may be repaired by constructing an intermediate volume-based model over one or more error zones that include the identified invalid 1D stratigraphic fibers, computing a paleo-depositional transform of the intermediate volume-based model by extracting a plurality of repaired horizon surfaces and a plurality of repaired 1D stratigraphic fibers to generate a surface-based representation to fix the error zones.
In accordance with some embodiments of the present invention, the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes may be updated by using arc-length parametrization between the edited positions of the plurality of control nodes when the updated geological data includes uniform layering between pairs of horizon surfaces.
In accordance with some embodiments of the present invention, the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes may be updated by adding secondary control nodes along the plurality of stratigraphic fibers at positions intersecting one or more intra-formational horizon surfaces in the updated geological data and interpolating segments of the plurality of stratigraphic fibers adjacent to the added secondary nodes.
In accordance with some embodiments of the present invention, the surface-based model may be locally edited by editing the plurality of control nodes within a 2D sub-surface of the surface meshes and intersecting 1D line segments of the stratigraphic fibers.
One or more processors may be used to execute methods disclosed herein for editing a volume-based model imaging geological structures, one or more memories may be used to store the updated volume-based model, and/or one or more displays may be used to visualize an image of the edited surface based model and/or updated volume-based model.

BRIEF DESCRIPTION OF EMBODIMENTS OF THE DRAWINGS

In order for the present invention to be better understood and for its practical applications to be appreciated, the following Figures are provided and referenced hereafter. It should be noted that the Figures are given as examples only and in no way limit the scope of the invention. Like components are denoted by like reference numerals.

Fig. 1 schematically illustrates a system for editing an image of geological structures by switching between volume-based and surface-based models, in accordance with some embodiments of the present invention;
Fig. 2A schematically illustrates an initial volume-based model, in accordance with some embodiments of the present invention;
Fig. 2B schematically illustrates input geological data used to edit a defined region of an initial volume-based model, in accordance with some embodiments of the present invention;
Fig. 3A schematically illustrates a volume-based model with a stratigraphic fiber defining stratigraphic layering, in accordance with some embodiments of the present invention;
Fig. 3B schematically illustrates a paleo-depositional representation of a portion of a volume-based model in a transformed domain including three distinct horizons and a fault, in accordance with some embodiments of the present invention;
Fig. 3C schematically illustrates a surface-based structural model generated by decomposing an initial volume-based model, in accordance with some embodiments of the present invention;
Fig. 4A schematically illustrates a surface-based model with initial geological data, in accordance with some embodiments of the present invention;
Fig. 4B schematically illustrates an edited surface-based model with updated geological data within a defined region and initial geological data outside of the defined region, in accordance with some embodiments of the present invention;
Fig. 5 schematically illustrates an edited surface-based model with sealed fault-horizon surface contacts, in accordance with some embodiments of the present invention;
Fig. 6 illustrates an edited surface-based model with updated stratigraphic fibers, in accordance with some embodiments of the present invention;
Fig. 7A schematically illustrates an edited surface-based model with two stratigraphic fibers, in accordance with some embodiments of the present invention;
Fig. 7B schematically illustrates a surface-based model with two stratigraphic fibers cutting through primary or reference horizon surfaces and intra-formational horizon surfaces, in accordance with some embodiments of the present invention;
Fig. 7C schematically illustrates a surface-based model with two stratigraphic fibers cutting an intra-formational horizon surface, in accordance with some embodiments of the present invention;
Fig. 8 schematically illustrates an updated volume-based model, in accordance with some embodiments of the present invention;
Fig. 9 is a flowchart depicting a method for editing a volume-based model imaging geological structures, in accordance with some embodiments of the present invention;
Fig. 10 is a flowchart depicting a method for improving the resolution of volume-based model imaging geological structures, in accordance with some embodiments of the present invention; and
Fig. 11 is a flowchart depicting a method for editing a volume-based model imaging geological structures, in accordance with some embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, modules, units and/or circuits have not been described in detail so as not to obscure the invention.
Although embodiments of the invention are not limited in this regard, discussions utilizing terms such as, for example, "processing," "computing," "calculating," "determining," "establishing", "analyzing", "checking", or the like, may refer to operation(s) and/or process(es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulates and/or transforms data represented as physical (e.g., electronic) quantities within the computer's registers and/or memories into other data similarly represented as physical quantities within the computer's registers and/or memories or other information non-transitory storage medium (e.g., a memory) that may store instructions to perform operations and/or processes. Although embodiments of the invention are not limited in this regard, the terms "plurality" and "a plurality" as used herein may include, for example, "multiple" or "two or more". The terms "plurality" or "a plurality" may be used throughout the specification to describe two or more components, devices, elements, units, parameters, or the like. Unless explicitly stated, the method embodiments described herein are not constrained to a particular order or sequence. Additionally, some of the described method embodiments or elements thereof can occur or be performed simultaneously, at the same point in time, or concurrently. Unless otherwise indicated, us of the conjunction "or" as used herein is to be understood as inclusive (any or all of the stated options).
Geological models, or computerized image representations of portions of the Earth's crust, may be generated using data such as seismic, geological and/or petrophysical measurements of geological layer strata and geological structures such as faults and horizons. The data may be based on measurements recording the reflection of acoustic or other waves at boundaries between layers within the Earth's subsurface. The waves may be emitted by a set of source devices and recorded by a set of receiver devices. Geological models may include, for example, a grid size and mesh specification, a geometric description of horizons and faults, and/or a 3D distribution of permeability and porosity in the rock layers in the geological strata. The geological models may then be used, for example, for property modeling, in which the different rock properties are spatially represented and mapped at each point or mesh node of the 3D grid.
These geological models may then be exported as inputs to a variety of simulators, such as flow and/or geomechanical simulators. Flow simulations may include reservoir simulations on a smaller scale, and basin simulation and modeling on a larger scale. Petrochemical parameters of the reservoir such as the hydrocarbon content volume and potential hydrocarbon yield in reservoirs may then be computed for evaluating hydrocarbon recovery. Ultimately improving the accuracy of these simulations may improve the success of exploration and production of hydrocarbon extracted from the modeled reservoirs.
The geological model including geological strata, horizons, faults and other subsurface structure may be represented in a present-day geological space, for example, using a Cartesian XYZ coordinate system. One approach to solving computational difficulties such as slow processing speeds due to complex and irregular subsurface geometries has been to apply a paleo-geological transform, for example, a UVT transform, to transform the present-day geological model (e.g., XYZ coordinates) into a paleo-geographic or depositional model (e.g., UVT coordinates) representing predicted approximate positions of particles of sediment deposited at a time period when the layer was originally formed. Instead of cutting or dividing the current or present-day geological model along fault and horizon lines, the paleo-geological transform converts the present-day geological model (e.g., in the XYZ coordinate system) into a past or paleo-depositional model (e.g., in a UVT coordinate system) and cuts the past paleo-depositional model along transformed fault and horizon lines.
The paleo-depositional model may represent an estimated state of the geological structure at a time period when the geological structure was originally formed. The vertical depth coordinate of the paleo-depositional model may measure the time period, t, of deposition. Since each horizon was generally deposited at approximately the same geological time (e.g., within a one to ten thousand year geological period), the horizon has a single constant depth coordinate (t) and therefore may be represented as a planar surface in the paleo-depositional model. Accordingly, the transformation or conversion from the present-day geological model (e.g., in XYZ space) to the paleo-depositional model (e.g., in UVT space) may flatten horizons from complex structures into flat, horizontal, or planar surfaces (e.g., iso-t surfaces).
Applying the paleo-geological transform to the present-day geological model may smooth or eliminate sharp, complex, or small-angle geometries normally found in the present-day (e.g., XYZ) coordinate system representation of the geological model. The computational speed, efficiency and convergence of simulators may thus be improved when computing different petrophysical metrics using the equivalent paleo-depositional (e.g., UVT) coordinate system for a given geological model. The paleo-geological transform is further described in U.S. Patent Publication No. 2013/0231903, filed April 27, 2012 .
Different simulators, for example, may be designed to use geological models based on a volume-based model and/or a surface-based model. Volume-based modeling may use geological models with 3D-polyhedral mesh elements such as for example tetrahedra. Volume-based models may include a present-day (e.g., XYZ) geological model with a polyhedral mesh and/or an equivalent depositional (e.g., UVT) model (e.g., related via a UVT transform). 2D surfaces of surface-based models may be represented by polygonal (e.g., triangular) mesh elements. Surface based models may treat, for example, each of the horizons with a polygon mesh in the geological model by the model.
Volume-based models may use less memory and may be more computationally efficient than surface-based models when used in simulators, for example, to determine various material properties or petro-physical metrics, since the simulator may simultaneously process all horizon and fault surfaces in a volume-based model. Volume-based models also ensure that horizons do not intersect each other within a stratigraphic sequence.
Volume-based models representing a particular region of the Earth may need to be updated with new geological data, for example, seismic data in a defined region of the model. New interpretations of the seismic data may replace the initial interpretations of the seismic data within a defined region of the model revealing a change in the geometry and topology of the horizon, faults and/or other geological stratigraphic layering. New interpretations of the seismic data may define an improved surface patch texture or topology (e.g., as shown in Fig. 2B) or an intersection between a horizon and fault (e.g., as shown in Fig. 5) within the defined region of the model. The initial volume-based model may be updated with the new geological data so as to improve model accuracy of the geological region in subsequent simulations.
In some embodiments of the present invention, a surface-based model may be generated from the volume-based model to represent each surface independently, without interconnection by a 3D polyhedral mesh between surfaces. Bundles of a plurality of 1D stratigraphic fibers each with control nodes forming the vertices of 2D surface polygonal (e.g., triangular) cells or mesh elements, for example, define the fault and horizon surfaces in the model. The control nodes may be moved independently of other surfaces to locally edit a defined region in accordance with the new geological data (e.g. input geological data). The local changes of the surface-based model to the new geological data edited within the defined region may be contained within the local defined region and may not propagate outside the defined region, for example, to other surfaces or globally throughout the geological model.
In contrast, editing a defined region using the volume-based models, for example, by moving nodes of the polyhedra to accommodate the shifts in the subsurface strata, may propagate local changes throughout the mesh outside the defined region, globally or to other surfaces. The horizons are iso-surfaces in a volume-based model with no physical nodes on these surfaces to modify. Editing the horizon surface within the defined region may be performed by modifying the values defined on the nodes of the polyhedral (e.g., tetrahedral) mesh of the volume-based model such that the iso-surfaces may change accordingly. In addition, editing a defined region in the present-day (e.g., XYZ coordinate) volume-based model may also alter the corresponding depositional (e.g., curvilinear UVT coordinate) model, or vice versa. For example, when a horizon is reshaped in the volume-based model in the present-day or depositional models, the transform there between is changed. Stated differently, to accommodate the new seismic interpretations and well measurements, the values at the nodes of the mesh in the depositional model may be updated to accommodate the new seismic interpretations and well measurements data in the defined region of the present-day geological model.
As substantially all nodes of a volume-based model are interconnected by a mesh, modifying a local defined region with new geological structural data, for example, from geological measurements such as seismic interpretations and well measurements, may propagate changes throughout the mesh, resulting in limited and non-intuitive user control over shape, resolution, and fit of the model to seismic interpretations and well data. If there are pre-existing structural models, it may be difficult to fully honor user-defined structural interpretations with the pre-existing structural model. Further, if the new data from the seismic and well measurements have relatively high resolution with relatively fine details, e.g., as compared to initial model data, it may be difficult to incorporate the new data into the volume-based model since the volume-based modeling may be incompatible with an incremental modeling workflow.
Embodiments of the present invention provide a device, system and method for updating a defined region of an initial volume-based model by switching to a surface-based model, editing the defined region with new geological data, and reverting back to the volume-based model.
The updated model may have new or edited geological data, such as a new horizon or fault surface patch or a new intersection surface between a fault and horizon, or other edits within the defined region, while the same initial data may remain in the remainder of the model outside the defined region. For example, the updated model may improve the resolution within a defined region, for example, incorporating new seismic interpretations and/or well data, while keeping a relatively low resolution mesh unchanged outside of the defined region. After the defined region has been edited, the model may be globally interpolated to re-apply the mesh to transform the updated surface-based model back into a volume-based model that has been locally edited. The defined region may include a sub-region or local region of the model, or may include the entire model. In the latter case, the entire model may be updated using the same flow described herein.
The edited volume-based model may be input into computer executed processes to generate improved property models, or in velocity modeling and seismic interpretation workflows. Switching back and forth between surface-based and volume-based models, according to embodiments of the invention, may provide the benefits of increased speed and efficiency afforded by intuitive editing in the surface-based model space, as well as increased speed and efficiency afforded by running processes in the volume-based space.
Fig. 1 schematically illustrates a system 105 for editing an image of geological structures by switching between volume-based and surface-based models, in accordance with some embodiments of the present invention. System 105 may include a transmitter 190, a receiver 120, a computing system 130 and a display 180.
Transmitter 190 may transmit output signals, for example, acoustic waves, compression waves or other energy rays or waves, that may travel through geological (e.g., below land or sea level) structures. The transmitted signals may become incident signals that are incident to geological structures. The incident signals may reflect at various transition zones or geological discontinuities throughout the geological structures. The output frequency, wavelength and intensity of the seismic signals by transmitter 190 may be controlled by a computing system, e.g., computing system 130 or another computing system separate from or internal to transmitter 190.
Receiver 120 may accept reflected signal(s) that correspond or relate to incident signals, sent by transmitter 190.
Transmitter 190 and receiver 120 made transmit/receive signals for making log-well measurements, where measurement equipment with transmitter 190, receiver 120, or both is lowered into a wellbore.
Computing system 130 may include, for example, any suitable processing system, computing system, computing device, processing device, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. Computing system 130 may include for example one or more processor(s) 140, memory 150 and software 160. Data 155 generated by reflected signals, received by receiver 120, may be transferred, for example, to computing system 130. The data may be stored in the receiver 120 as for example digital information and transferred to computing system 130 by uploading, copying or transmitting the digital information. Processor 140 may communicate with computing system 130 via wired or wireless command and execution signals.
Memory 150 may include cache memory, long term memory such as a hard drive or disk, and/or external memory external to processor 140, for example, including random access memory (RAM), read only memory (ROM), dynamic RAM (DRAM), synchronous DRAM (SD-RAM), flash memory, volatile memory, non-volatile memory, cache memory, buffer, short term memory unit, long term memory unit, or other suitable memory units or storage units. Memory 150 may store data 155 and instructions (e.g., software 160 such as instructions for the processor to perform the meshing of cells along boundary topologies of interesting horizons with faults in a geological model as described herein), which when executed perform embodiments of the invention. Data 155 may include, for example, raw seismic data collected by receiver 120, instructions for partitioning a 3D mesh, grid or other arrangement into polyhedron, instructions for building a model, instructions for converting or transforming (and inverse transforming) a model between a present-day geological model and a past paleo-depositional model, a present-day geological model (including, for example, a set of sub-mesh parts each including present-day geological data), a volume-based model, or a surface-based model. When discussed herein, manipulating geological data, such as the operations for calculating, forming, cutting, dividing, etc., cells or sub-meshes, may involve the manipulation of data stored in memory 150 which represents the corresponding geological structures, the cells, sub-meshes, sub-mesh parts, horizons or faults. The geological model after processing the faults in accordance with some embodiments of the present invention may be store in memory 150.
Processor 140 may include a local or internal memory 145, such as a cache memory, for relatively fast access to data, e.g., as compared to memory 150.
Input device(s) 165 may include a keyboard, pointing device (e.g., mouse, trackball, pen, touch screen), or cursor direction keys, for communicating information and command selections to processor 140. Input device 165 may communicate user direction information and command selections to processor 140. For example, a user may use input device 165 to select or toggle between displaying a present-day geological model and a past paleo-depositional model of the same geological structure, to select or toggle between displaying or generating a volume-based model and a surface-based model, select a model mode, edit, perform geometrical computations, highlight models, etc.
A display 180 may output a visualization or image of the geological model, for example, generated based on operations executed by processor 140. Display 180 may display data from transmitter 190, receiver 120, or computing system 130. For example, display 180 may display visualizations of surface-based models and/or volume-based models.
Embodiments of the present invention may manipulate data representations of real-world objects and entities such as underground geological features, including faults, horizons and other features such as unconformities or salt bodies. Data received by, for example, receiver 120 receiving waves generated by an air gun or explosives may be manipulated and stored, e.g., in memory 150, and data such as images representing underground features may be presented to a user, e.g., as a visualization on display 180.
In some embodiments of the present invention, editing the volume-based model with new geological data defined within a region of the model may include inputting an initial volume-based surface model and user input data (e.g., input geological data) to system 105. Typically the initial volume-based models may have been derived from initial geological data in the defined region of the model. In various embodiments, the initial volume-based surface model may be derived from a surface-based model or may be derived from a depositional model by using a reverse domain transform. The initial volume-based surface model may be derived using interpolated geological data. In some embodiments, the initial volume-based surface model may have an initial low resolution mesh.
A user of system 105 or processor may determine that the initial volume-based surface model may not include enough resolution in certain higher resolution features of the geological structure and stratigraphy to accurately model the desired petrophysical parameters by a geostatistical simulator, for example. Over time, there may be certain high resolution features in a defined region of the geological model that were not previously included in the initial volume-based model. For example, the subsurface strata may include new improved data further defining fault lines and/or new horizon surfaces, and in some cases, new geological features that may have occurred in a short time interval since the initial model survey, for example, due to an earthquake. The user may choose to locally edit portions of the model using new or updated geological data (e.g., input data), which provides improved resolution data or new high resolution features in modeling the geological structure and stratigraphy. The new or updated geological input data may be generated based on real world reflections of the seismic waves through the subsurface strata as measured by transmitter 190 and receiver 120 in system 105. The updated geological data may include geological data of the same geological region that is modeled in the initial geological model, but which may include higher resolution than that of the same region in the initial geological model, and that may be used to refine the initial geological model.
Fig. 2A illustrates an initial volume-based model 200, in accordance with some embodiments of the present invention. Initial volume-based model 200 may include geological structures such as faults 215 and horizon surfaces 220. Initial volume-based model 200 may be populated by a mesh 225, which may include polyhedral cells such as tetrahedral cells, for example. An initial volume-based model 200 may include a geological model in a present-day coordinate space (e.g., XYZ Cartesian coordinate space) and/or a corresponding depositional coordinate space (e.g., UVT coordinate space).
Fig. 2B schematically illustrates input geological data 210 used to edit a defined region 217 of an initial volume-based model 200, in accordance with some embodiments of the present invention. Horizons 220 in Fig. 2B may represent the same geological structures as horizons 220 in volume-based model 200 in Fig. 2A. The initial volume-based model 200 may be derived from initial geological data. The input geological data 210 may include high resolution data of the geometry and topology of horizon surfaces 220 and/or fault 215 such as the surface peak and valley structures in a region 217, relative to the resolution of the same region in initial volume-based model 200. Input geological data 210 may capture details in geometry and topology in horizons 220 and fault 215, which occurred after the measurement of the initial geological data was recorded (e.g., due to recent tectonic shifts) such as a carbonite layer, for example, which may be easily deformed.
In some embodiments of the present invention, the initial volume-based model may be generated with high resolution geometry and topological features, but with higher computational cost in honoring the seismic and/or well data for the initial volume-based model. The initial volume-based model may be generated so as to validate and capture the primary features of the geological structure such as primary horizons and faults, for example. Improving the resolution of the volume-based model may include assessing that there may be a need for improved-resolution models. If an improved resolution model may be needed in a defined region of the initial volume-based model, the defined region may be edited incrementally without affecting the rest of the model.
Fig. 3A schematically illustrates volume-based model 200 with a stratigraphic fiber 255 defining stratigraphic layering, in accordance with some embodiments of the present invention. Stratigraphic fiber 255 may define the stratigraphy, stacking, or vertical layering or density of horizon and intra-formational surfaces. Stratigraphic fiber 255 may include an Iso-Paleo-Geological (IPG) line having constant paleo-depositional coordinates and varying in geological time.
Volume-based model 200 (e.g., as in Fig. 2A) may include a plurality of horizons 221, 222, and 223 that are cut by fault 215. Distinctions made in designating three horizon surfaces 221, 222, and 223 from among horizons 220 shown in Fig. 2A are made merely for visual clarity for comparing the same horizon surfaces in the following figures (e.g., Figs. 3B and 3C) and the input geological data (Fig. 2B). Stratigraphic fiber 255 may be approximately orthogonal (but not limited to since there are different styles of deformation) to horizon surfaces 221, 222, and 223. Stratigraphic fiber 255 may define the spacing between layers or the density of stratigraphic layering.
Fig. 3B schematically illustrates a paleo-depositional model representation 200A of a portion of volume-based model 200 in a transformed domain including three distinct horizons 221, 222, and 223 and fault 215, in accordance with some embodiments of the present invention. Paleo-depositional model 200A, such as a UVT model, for example, may represent a model at a time when the geological layers were originally deposited in the Earth. The effect of the domain transform on the volume-based model 200 in Fig. 3A may flatten horizon surfaces across fault 215 as shown in Fig. 3B.
Stratigraphic fiber 255 may be an intersection between iso-surfaces of paleo-geographic coordinates (e.g., u iso-surfaces and v iso-surfaces) in the depositional (e.g., UVT) coordinate space of the paleo-depositional model, where the values of paleo-geographic coordinates (e.g., u,v) are constant along the stratigraphic fiber 255 as the geological-time coordinate (e.g., t or tectonic time coordinate) changes. Thus, stratigraphic fiber 255 may be parallel to the t-axis in depositional (e.g., UVT) space and may orthogonally cut horizons 221, 222, and 223, flattened in depositional (e.g., UVT) space. However, a continuous stratigraphic fiber (e.g., IPG line) in depositional space (e.g., UVT space) may include several segments in XYZ space as in stratigraphic fiber 255 in Fig. 3A
In some embodiments of the present invention, in order to update or edit structure and stratigraphy separately, in a defined region of the volume-based model with new geological data, volume-based model 200 may be decomposed into a sealed surface-based model including a plurality of distinct faults and/or horizon surfaces linked by a plurality of stratigraphic fibers (e.g., IPG lines) approximately orthogonal to the distinct horizon surfaces. The fault and/or horizon surfaces may be a subset of faces of the volumetric mesh or may be iso-value surfaces of level sets defined on the volumetric mesh in the initial volume-based model. Stated differently, the plurality of fibers may include a bundle of stratigraphic fibers. Each of the stratigraphic fibers includes one or more control nodes, where each of the control nodes may be located on a particular horizon and/or fault surface, and/or other geological structures, such as unconformities and salt bodies, for example. Thus, each of the horizon and/or fault surfaces may be formed by a plurality of control nodes along a plurality of stratigraphic fibers located on each of the horizon and/or fault surfaces.
The defined region of the decomposed surface-based model may be edited with the geological input data by moving the plurality of control nodes in the defined region to fit the substantially similar horizon and/or fault surfaces in the geological input data that may include more geometric and/or topological features not captured in the initial volume-based model. After editing the surface-based model by moving the control nodes on the stratigraphic fibers, the plurality of distinct horizon surfaces along with the plurality of stratigraphic fibers may be meshed to generate the updated volume-based model with the geological input data with an improved-resolution mesh.
Fig. 3C schematically illustrates a surface-based structural model 240 generated by decomposing an initial volume-based model 200, in accordance with some embodiments of the present invention. To edit a defined region in volume-based model 200 in Fig 3A, volume-based model 200 may be decomposed into a surface-based structural model 240 with a plurality of stratigraphic fibers 255 (e.g., IPG lines 255). The defined region in the surface based structural model may include a surface patch 253 defined on horizon surface 221, for example. In some embodiments, the defined region of surface-based structural model 240 may include the entire model 240, or a sub-region, or a section of surface-based structural model 240. Defined region 253 may include a defined 3D volume in which the plurality of stratigraphic fibers 255 may pass so as to edit multiple horizon surfaces within the defined 3D volume as shown in Figs. 4A and 4B.
In some embodiments of the present invention, the plurality of stratigraphic fibers may be visually represented as IPG lines such as IPG line 255. Each of the stratigraphic fibers such as stratigraphic fiber 255 may include IPG lines along with a geological time at each point along the IPG line. Stratigraphic fiber 255 may include which may have control nodes 235 on the respective faults and horizon surface, traversed by the IPG lines. Control nodes 235 along IPG line may be separated by segments 237. The geological time may be defined at control nodes 235 and may use polynomial curves interpolating between control nodes to model segments 237. Thus the geological time may be defined by use of interpolating polynomial curves such as a spline, for example. In some embodiments, the segments may be represented by piecewise-linear curves. A family of control nodes may be located on the same fault and/or horizon forms the horizon and/or fault surface. These fault and/or surfaces may form the sealed structural model.
These horizon and/or fault surfaces may be represented as piecewise-linear polygonal (e.g., triangular) meshes as in a classic surface-based structural model. The geometries of the stratigraphic fibers (e.g., IPG lines) may be given by the polynomials. The associated u and v coordinates of each stratigraphic fiber (e.g., IPG line) may be known. The geological-time (t) coordinate may be defined on each control node 235. The t-function representing a segment between two control nodes along a stratigraphic fiber may be an interpolation of the values on control nodes, such as a linear combination of the values on the control nodes.
In some embodiments of the present invention, the geological-time (t) value of a point between two control nodes may be defined by a linear combination of the two control node values based on interpolation, such as for example, in barycentric coordinates, computed from the parametrization of the curve. Controlling the parameterization of the polynomial curve along segments 237 may control how geological time t varies along the curve, which is another property of a stratigraphic fiber. A bundle of stratigraphic fibers may span a subdomain of the UV plane.
In some embodiments of the present invention, a stratigraphic fiber may define an IPG line 255 with a geological time, such as an associated spline function, for example. Alternatively or additionally, a stratigraphic fiber may be visually represented as a transverse line (e.g., IPG line 255). The stratigraphic fibers in surface-based structural model 240 may be used to maintain information regarding the geological or tectonic time (t) when transforming surface-based structural model 240 back to volume-based model 200 and/or 200A. Upon editing surface-based structural model 240 with new geological data, surface-based structural model 240 with stratigraphic fibers 255 may be used to reconstruct the edited volume-based model such that maintaining accuracy in the t functions associated with the IPG line representation may be useful in accurately reconstructing the edited volume-based model. In some embodiments of the present invention, region 253 includes a bundle of stratigraphic fibers 255 with respective control nodes 235 such as on horizon surface 221, for example.
Fig. 4A schematically illustrates surface-based model 240 with initial geological data, in accordance with some embodiments of the present invention.
Fig. 4B schematically illustrates an edited surface-based model 270 with updated geological data 210 (e.g., from Fig. 2B) within a defined region and initial geological data (e.g., from Fig. 4A) outside of a defined region, in accordance with some embodiments of the present invention. The updated geological data may be higher resolution than the defined region in the initial volume-based model. For example, region 253 (e.g., a surface patch) on horizon 221 and another region 230 (e.g., a 3D volume) may be edited with input geological data 210. A bundle with a high density of stratigraphic fibers 265 passing through 3D region 230 may determine the resolution of the final updated regions, for example, to capture peaks and valleys 275 shown in 3D volume region 230, obtained from the geometry and topology of the input geological data of region 217 shown in Fig. 2B. In some embodiments, the user may define the region to be any suitable size or include any number of horizons and/or faults. In some embodiments, the defined region may include larger regions in the model, or may include the entire model.
In some embodiments of the present invention, editing volume-based model 200 with the new geological data may include deforming the geometry and topology or updating data in one or more defined regions of surface-based structural model 240 using the input geological data 210 for the same or overlapping regions in Fig. 2B. Deforming the geometry and topology of the one or more defined regions may include moving control nodes 235 along stratigraphic fiber 255 to match points on the respective defined regions in the input geological data 210.
In some embodiments of the present invention, control nodes may be moved along stratigraphic fibers intersecting faults and horizon surfaces using Geological Time Refinement (GTR) methodology set forth in U.S. Patent Application number 14/743,118, filed June 18, 2015 .
In some embodiments of the present invention, editing volume-based model 200 may include altering surface-based model 240 using input geological data 210 only within the defined region and not outside of the defined region.
In some embodiments of the present invention, editing volume-based model 200 may include altering all of the surface-based model 240 globally using input geological data 210 where the defined region is the entire surface based structural model.
In some embodiments of the present invention, editing volume-based model 200 may include altering surface-based model 240 using input geological data 210 only within one or more defined regions and not outside of the one or more defined region. The one or more defined regions may be edited simultaneously or iteratively one after the other.
Bottom left side inset 262 of Fig. 4A shows a stratigraphic fiber 265 (e.g., an IPG line 265) to be edited that includes control node 267 in second defined region 230 located on horizon surface 223. Inset 262 shows that stratigraphic fiber 265 includes points Γ(u,v,t₁) and Γ(u,v,t_n) at different tectonic times t₁ and t_n, respectively. Control node 267 on stratigraphic fiber 265 may be located on horizon 223. Control node 267 at a point r_n may be located in a polygonal mesh element (e.g., a triangular element) denoted C (e.g., in a Cartesian coordinates x, y, z). Control node r_n (e.g., control node 267) may be edited or moved along stratigraphic fiber 265 to match the input data in defined region 217 of surface-based model 210 shown in Fig. 2B.
In some embodiments of the present invention, a bundle of stratigraphic fibers including stratigraphic fiber 265 may intersect a respective plurality of initial control nodes on horizon surface 223 such as control node 267, for example, in 3D region 230. The position of these control nodes may be moved along the stratigraphic fibers in the bundle in 3D volume region 230 to fit the geometry and topology in input geological data in region 217 as shown in Fig. 2B. The resolution may be based on the density and/or number of stratigraphic fibers in the bundle in 3D region 230. Editing the initial geological data to conform to the input geological data may yield edited surface based model 270 in Fig. 4B with an improved and/or higher resolution geometry and topology 275 on horizon 223 relative to that shown in 3D region 230 in initial surface based model 240 of Fig. 4A or initial volume-based model 200 of Fig. 3A.
In some embodiments of the present invention, the defined region may include multiple horizon surfaces with multiple control nodes. Editing the defined region may include moving the multiple control nodes, for example, simultaneously or sequentially, along stratigraphic fibers in the defined region so as to fit the input geological data in the respective defined region. In some embodiments, GTR methodologies may be used by solving a system of linear equations.
In some embodiments of the present invention, the defined region may include the entire geological model 260. Editing the defined region may include globally moving control nodes along stratigraphic fibers traversing multiple horizon surfaces and/or faults so as to fit the input geological data.
Fig. 5 schematically illustrates an edited surface-based model 280 with sealed fault-horizon surface contacts 295, in accordance with some embodiments of the present invention. After moving control nodes along a bundle of stratigraphic fibers (e.g., IPG lines) intersecting a given horizon surface so as to deform the given horizon surface to match the geological input data, the control nodes may pass through a fault and/or through another horizon surface.
Stratigraphic fibers with control nodes on the given horizon surface which pass through a fault and/or another horizon surface may collide with polygonal mesh elements on the fault and/or on other horizon surfaces. For example, stratigraphic fiber 265 associated with polygonal mesh element C may be invalidated when moving control node 267 in Fig. 4A through fault 215. Polygonal mesh elements of the horizon surfaces, for example, that intersect faults and/or other horizon surfaces are removed from the mesh which may leave the structural model unsealed. Stratigraphic fibers intersecting these polygonal mesh elements are invalidated.
An invalid stratigraphic fiber zone may be a volume or sub-region of edited surface-based model 280 with sealed fault-horizon surface contacts 295 which include one or more invalid stratigraphic fibers passing through the region or sub-region. With multiple invalid stratigraphic fibers, the accuracy of the updated volume-based model may be reduced (e.g., upon converting edited surface-based model 280 to generate the updated volume-based model). The tectonic time t information lost due to the multiple invalid stratigraphic fibers may, however, be repaired or updated as described below.
In some embodiments of the present invention, GTR methodologies may be used to move the control points along bundles of stratigraphic fibers to prevent control nodes from crossing horizon surfaces and/or fault surfaces. However, by using GTR methodologies there may not be invalid stratigraphic fibers after moving the control points.
Fig. 6 illustrates an edited surface-based model 282 with updated stratigraphic fibers 296, in accordance with some embodiments of the present invention. The invalid stratigraphic fibers may be updated, or repaired, in the identified invalid stratigraphic fiber zones surrounding sealed fault-horizon surface contacts 295 within edited surface-based model 280 (e.g., as shown in Fig. 5). An intermediate volume-based model may be constructed only in the identified invalid stratigraphic fiber zones. A domain (e.g., UVT) transform honoring the updated surface based structural model 280 and the valid stratigraphic fibers outside the zone may be computed in the multiple identified invalid stratigraphic fiber zones. The domain transform on the intermediate volume-based model may be used to retrieve the lost tectonic t information in the multiple identified invalid stratigraphic fiber zones. The intermediate volume-based model may then be decomposed, e.g., using the same methodology described in reference to Figs. 3A-3C, resulting in edited surface-based model 282 with repaired stratigraphic fibers 296 shown in Fig. 6.
In some embodiments of the present invention, globally converting surface-based model 280 into a volume-based model where the defined region may include the entire surface based structural model 280 may represent the case where there are no valid stratigraphic fibers. In this case, all of the invalid stratigraphic fibers may be repaired.
In some embodiments of the present invention, the initial volume-based model may be constructed using primary horizon surfaces and faults in the initial geological data over a defined region. There may be additional intermediate or intra-formational horizons in the input geological data defining the stratigraphic layering of surfaces between reference horizons within the defined region of the model being edited including information on stratigraphy within two primary faults and/or between a fault and a horizon that may be used to further improve the accuracy of the t functions in the interpolation of polynomial curves between control nodes of the stratigraphic fibers (e.g, along segments 237). The stratigraphy may be edited to match the resolution of the input geological data. Secondary control nodes may be placed on the stratigraphic fibers, for example, as described in reference to Fig. 7C.
Fig. 7A schematically illustrates an edited surface-based model 300 with two stratigraphic fibers 302 and 304, in accordance with some embodiments of the present invention. Edited surface based model 300 may be based on edited surface-based model 282 with updated stratigraphic fibers 296 (e.g., as shown in Fig. 6). Control nodes 309 include new control nodes on horizon surfaces 221, 222, and 223 generated by editing or moving the initial control nodes along 1D stratigraphic fibers.
Fig. 7B schematically illustrates a surface-based model 305 with two stratigraphic fibers 306 and 308 cutting through primary or reference horizon surfaces 221, 222, and 223 and intra-formational horizon surfaces 307, in accordance with some embodiments of the present invention. The two stratigraphic fibers 306 and 308 may have uniform layering between pairs of the horizon surfaces. In this case, arc-length parametrization of stratigraphic fibers 306 and 308 may be used in the geological time t-function computation. In this case, control nodes 309 are fixed in position as well as their t values as the t function along the polynomial curve segments (e.g., segments 237) between control nodes may be modified.
Fig. 7C schematically illustrates a surface-based model 315 with two stratigraphic fibers 320 and 325 cutting an intra-formational horizon surface 310, in accordance with some embodiments of the present invention. Intra-formational horizon 310 denoted H_t may be located between two primary horizon surfaces 340 and 345 denoted, for example, as H_ti+1 and H_ti, respectively. Control nodes on stratigraphic fibers 320 and 325 may be denoted by maximum (e.g., geological time t=1) and minimum (e.g., geological time t=0) values on horizon surfaces H_ti+1 and H_ti, respectively. A different approach is taken here due to the curvature of the intra-formational horizon surfaces to further improve the accuracy and/or resolution of the stratigraphy or the geological time of the polynomial curves associated with the interpolation between the two maximum and minimum control nodes of stratigraphic fibers 320 and 325. For example, control points may be placed on the intra-formational horizon surface Ht at t=t_Ht. In some embodiments, secondary control nodes denoted λ₁ and λ₂ may be added locally such that the value of geological time t at control node λ₁ of IPG(ui, vi) may be equal to that of control node λ₂ of IPG(u₂, v₂).
In some embodiments of the present invention, GTR methodologies may be used to compute the position of the secondary control nodes and the new coefficients of the refined polynomial curves associated with the stratigraphic fibers in subsurface structural model 300.
Fig. 8 schematically illustrates an updated volume-based model 400, in accordance with some embodiments of the present invention. Updated volume-based model 400 may include fault 215 and horizon surfaces 220, which may be generated by meshing or discretizing the domain (e.g., UVT) functions defined on edited surface-based model 300 including the stratigraphic fiber bundle that has been edited with input geological data in one or more edited regions 410.
In some embodiments, the surfaces of the structural model may be used as a constraint in the meshing process. The control nodes of the 2D surface mesh (e.g., forming the vertices of the 2D polygonal mesh cells) forming the surfaces of the edited surface based model may be completely honored in the updated volume-based model. As a result during meshing, the polyhedral 3D mesh may have nodes that are coincident with horizon surfaces 220 as shown for example in a marker 420 showing nodes along the horizon surfaces in contrast to the 3D polyhedral mesh in the initial volume-based model where the 3D polyhedral cells may have few nodes along the horizon surfaces as shown in Fig. 2A.
In some embodiments of the present invention, meshing edited surface-based model 300 with 3D polyhedral cells (e.g., tetrahedral cells) may include forming the volumetric mesh with a subset of 3D cells having nodes constrained to the edited positions of the control nodes. Stated differently, meshing (e.g. by using constrained Delaunay tessellation) edited surface-based model 300 with 3D polyhedral cells (e.g., tetrahedral cells) may include meshing surface-based model 300 with 3D cells where a subset of 3D cells have nodes constrained to the plurality of control nodes at the intersections of the 2D surface cells and the 1D stratigraphic fibers (e.g., where the intersections are alternatively the edited positions of the control nodes.) There may be more cells between horizon and fault surfaces where the geological time of some segments in the plurality of stratigraphic fibers may exhibit higher gradients, that is, where the geological time may change faster on some stratigraphic fibers relative to others.
Outside edited regions 410, updated volume-based model 400 may retain the initial resolution of polyhedral mesh 225 (e.g., tetrahedral mesh elements) in the initial volume-based model 200. Inside edited regions 410, updated volume-based model 400 may have an improved or increased resolution mesh (e.g., with higher polyhedral mesh density) compared to the initial mesh resolution. Generally, the polyhedral mesh density may be higher wherever there may be large variations in the shape of the horizon and/or fault surfaces in the structural model, or wherever there may be a large gradient in the geological time t function of the stratigraphic fibers. The gradient may be used as a constraint in the tessellation process to have more 3D cells where the gradient may be higher some stratigraphic fibers relative to others.
In some embodiments of the present invention, a plurality of nodes may be edited that do not align with horizons in the initial volume-based model to have edited positions that align with horizons in the updated volume-based model.
Fig. 9 is a flowchart depicting a method 500 for editing volume-based model 200 imaging geological structures, in accordance with some embodiments of the present invention. In the example of Fig. 9, method 500 may be executed by processor 140 of system 105. Method 500 may be executed upon a request or command that is issued by a user, or automatically issued by another application.
Method 500 may include receiving 510 an initial volume-based model including a volumetric mesh. Method 500 may include receiving 515 updated geological data defined within a region of the model. Method 500 may include decomposing 520 the initial volume-based model by converting the volumetric mesh into a plurality of surface meshes linked by a plurality of stratigraphic fibers to generate a surface-based model. Method 500 may include editing 525 the defined region of the surface-based model by editing positions of a plurality of control nodes of the surface meshes along the plurality of stratigraphic fibers in the defined region of the model so as to fit the updated geological data.
Method 500 may include updating 530 the plurality of stratigraphic fibers, for example, by updating the geological time associated, based on the edited positions of the plurality of control nodes so as to fit the updated geological data.
In various embodiments, updating 530 the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes may include using arc-length parametrization between the edited positions of the plurality of control nodes when the updated geological data includes uniform layering between pairs of horizon surfaces.
Updating 530 the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes may include adding secondary control nodes along the plurality of stratigraphic fibers at positions intersecting one or more intra-formational horizon surfaces in the updated geological data and interpolating the plurality of edited 1D stratigraphic fibers and/or geological time along segments of the plurality of stratigraphic fibers adjacent to the added secondary nodes.
Method 500 may include meshing 535 the edited surface-based model to generate an updated volume-based model including a volumetric mesh defined by the edited positions of the control nodes. Method 500 may include storing 540 the updated volume-based model.
Fig. 10 is a flowchart depicting a method 600 for improving the resolution of volume-based model 200 imaging geological structures, in accordance with some embodiments of the present invention. In the example of Fig. 10, method 600 may be executed by processor 140 of system 105. Method 600 may be executed upon a request or command that is issued by a user, or automatically issued by another application.
Method 600 may include receiving 610 an initial volume-based model having initial geological data defined by a volumetric mesh including 3D cells. Method 600 may include receiving 615 updated geological data defined within a region of the model. Method 600 may include converting 620 the volume-based model into a surface-based model of the initial geological data defined by a plurality of distinct surface meshes including 2D cells that form a plurality of horizon and fault surfaces linked by a plurality of 1D stratigraphic fibers defining the stratigraphic spacing between surfaces.
Method 600 may include editing 625 the defined region of the surface-based model by editing the positions of a plurality of control nodes at the intersections of the 2D cells and the 1D stratigraphic fibers to conform to the updated geological data in the defined region of the model. In some embodiments, locally editing 625 the surface-based model may include editing the plurality of control nodes within a 2D sub-surface of the surface meshes and intersecting 1D line segments of the stratigraphic fibers.
Method 600 may include converting 630 the edited surface-based model of edited 2D cells and edited 1D stratigraphic fibers into an updated volume-based model of edited 3D cells. Method 600 may include storing 635 the updated volume-based model.
Fig. 11 is a flowchart depicting another method 700 for editing a volume-based model 200 imaging geological structures, in accordance with some embodiments of the present invention. In the example of Fig. 11, method 700 may be executed by processor 140 of system 105. Method 700 may be executed upon a request or command that is issued by a user, or automatically issued by another application.
Method 700 may include receiving 710 a volume-based model and input geological data defined with a region of the model. Method 700 may include decomposing 715 the volume-based model to a surface-based model with multiple fault and horizon surfaces orthogonally cut by multiple stratigraphic fibers. Method 700 includes moving 720 control nodes along the multiple stratigraphic fibers in the defined region so as to deform the multiple fault and horizon surfaces to fit the input geological data.
In some embodiments the present invention, an invalid stratigraphic fiber may be identified from the plurality of stratigraphic fibers when the edited position of a control node along the stratigraphic fiber crosses to a different edited surface than initially positioned.
Method 700 may include repairing 725 invalid stratigraphic fibers in invalid fiber zones (e.g., error zones) by creating an intermediate volume-based model in the invalid fiber zones and decomposing the intermediate volume-based model.
In some embodiments, repairing 725 the invalid stratigraphic fibers may include repairing the identified invalid 1D stratigraphic fibers by constructing an intermediate volume-based model over one or more error zones that include the identified invalid 1D stratigraphic fibers, computing a paleo-depositional transform of the intermediate volume-based model by extracting a plurality of repaired horizon surfaces and a plurality of repaired 1D stratigraphic fibers to generate a surface-based representation to fix the error zones.
Method 700 may include improving 730 the accuracy of polynomial curves associated with the repaired stratigraphic fibers by using transformation horizon surfaces in the input geological data with the control nodes fixed. Method 700 may include remeshing 730 the surface-based structural model to generate the final updated volume-based model.
In some embodiments of the present invention, editing the volume-based model by moving control nodes along bundles of stratigraphic fibers with input geological data in a defined region of the model may assume that the horizon surfaces and faults are substantially similar in the input geological data. Stated differently, the initial volume-based model may be sufficiently close to the final volume-based model. In cases where new substantially different features (e.g., new faults and horizon surfaces) arise in the new geological data, the new features can be added to the volume-based model iteratively using the steps of method 500, for example, such that the updated volume-based model becomes the initial volume-based model in the next iteration to add the new, substantially different features in the input geological data to the volume-based model.
In some embodiments of the present invention, receiving 510 the initial volume-based model may include receiving an initial surface-based model and meshing the initial surface-based model to convert into the initial volume-based model. In some embodiments of the present invention, an initial paleo-depositional transform of the meshed initial surface-based model may be computed to generate a geological time of approximate time periods when particles of sediment were originally deposited to define the stratigraphy of surfaces in the initial volume-based model.
It should be understood with respect to any flowchart referenced herein that the division of the illustrated method into discrete operations represented by blocks of the flowchart has been selected for convenience and clarity only. Alternative division of the illustrated method into discrete operations is possible with equivalent results. Such alternative division of the illustrated method into discrete operations should be understood as representing other embodiments of the illustrated method as defined by the appended claims.
Similarly, it should be understood that, unless indicated otherwise, the illustrated order of execution of the operations represented by blocks of any flowchart referenced herein has been selected for convenience and clarity only. Operations of the illustrated method may be executed in an alternative order, or concurrently, with equivalent results. Such reordering of operations of the illustrated method should be understood as representing other embodiments of the illustrated method as defined by the appended claims.
Different embodiments are disclosed herein. Features of certain embodiments may be combined with features of other embodiments; thus certain embodiments may be combinations of features of multiple embodiments. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It should be appreciated by persons skilled in the art that many modifications, variations, substitutions, changes, and equivalents are possible in light of the above teaching as defined by the appended claims.
While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art.

Claims

A method implemented in a computing system of editing a volume-based model imaging geological structures, the method comprising:
receiving an initial volume-based model having initial geological data defined by a volumetric mesh (610) comprising 3D cells;

receiving (615) updated geological data defined within a region of the volume-based model;

converting (620) the initial volume-based model into a surface-based model of the initial geological data defined by a plurality of distinct surface meshes comprising 2D cells that form a plurality of horizon and fault surfaces linked by a plurality of 1D stratigraphic fibers defining the stratigraphic spacing between surfaces;

editing (625) a defined region of the surface-based model converted from the defined region of the initial volume-based model by editing the positions of a plurality of control nodes at the intersections of the 2D cells and the 1D stratigraphic fibers to conform to the updated geological data in the defined region;

converting (630) the edited surface-based model comprising edited 2D cells and edited 1D stratigraphic fibers into an updated volume-based model of edited 3D cells; and

storing (635) the updated volume-based model.
The method according to claim 1, wherein receiving the initial volume-based model comprises receiving an initial surface-based model and meshing the initial surface-based model to convert the initial surface-based model into the initial volume-based model.
The method according to claim 2, comprising computing an initial paleo-depositional transform of the initial surface-based model to generate a geological time of approximate time periods when particles of sediment were originally deposited to define the stratigraphy of surfaces in the initial volume-based model.
The method according to any preceding claim, wherein the plurality of 1D stratigraphic fibers are Iso-Paleo-Geological (IPG) lines having constant paleo-depositional coordinates and varying in geological time.
The method according to any preceding claim, comprising identifying an invalid 1D stratigraphic fiber from the plurality of 1D stratigraphic fibers when the edited position of a control node along the 1D stratigraphic fiber crosses to an edited surface that is different than a surface on which the control node is initially positioned.
The method according to claim 5, comprising repairing the identified invalid 1D stratigraphic fibers by constructing an intermediate volume-based model over one or more error zones that include the identified invalid 1D stratigraphic fibers, computing a paleo-depositional transform of the intermediate volume-based model by extracting a plurality of repaired horizon surfaces and a plurality of repaired 1D stratigraphic fibers to generate a surface-based representation to fix the error zones.
The method according to any preceding claim, comprising updating the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes by using arc-length parametrization between the edited positions of the plurality of control nodes when the updated geological data includes uniform layering between pairs of horizon surfaces.
The method according to any preceding claim, comprising updating the plurality of edited 1D stratigraphic fibers based on the edited positions of the plurality of control nodes by adding secondary control nodes along the plurality of stratigraphic fibers at positions intersecting one or more intra-formational horizon surfaces in the updated geological data and interpolating segments of the plurality of edited stratigraphic fibers adjacent to the added secondary nodes.
The method according to any preceding claim, comprising locally editing the surface-based model by editing the plurality of control nodes within a 2D sub-surface of the surface meshes and intersecting 1D line segments of the stratigraphic fibers.
A system for editing a volume-based model imaging geological structures, the system comprising:
a processor;

a memory;

one or more instructions stored in the memory, which, when executed, configure the processor to perform a method according to any of the previous claims.
A computer-readable medium comprising instructions which, when implemented in a processor in a computing system, cause the processor to perform a method according to any of claims 1-9.